Netapp LUN for Redhat enterprise Linux 7.7 with DM-Multipathing

[FelixZhou]

We are working on NetApp (AFF300 7.6P5) with Redhat enterprise Linux 7.7 with DM-Multipahing. We plan to mirror local device to NetApp with Linux native LVM. Then use NetApp to replicate the volume to remote site for a DR application server. But we encountered some issues. Can somebody share your experience?

1). First of all, we couldn't make the DM-Multipath working properly with NetApp. We created a multipath.conf for NetApp, we did see NetApp multipath device but looks the device is unstable (path down and up), we doubt the multipath.conf is not set up correctly, can someone share yours as example?

On the multipath.conf, we have to change the product value to "LUN" for vendor "(LSI|NETAPP)" to see the LUN, not sure if it is correct.

the individual device is accessible and stable, i assume we are having issue on multipath device.

2. we plan to use local device (SSD) as primary copy, then use LVM mirroring to make second copy to NetApp LUN. Replicate the Netapp volume to different location. is that a good practice?

thanks

[AlexDawson]

Hi there! Best place to start is our iSCSI Redhat Power guide at http://docs.netapp.com/ontap-9/topic/com.netapp.doc.exp-iscsi-rhel-cg/iSCSI%20express%20configuration%20for%20Red%20Hat%20Enterprise%20Linux.pdf

Once you have that working.. have a look at if what you want to do is the best idea for your environment.

I honestly don't think it's a good idea - I'm always one to check before saying no, but I found other people online referring to this sort of arrangement as "terrible".  You won't have control over when the sync happens, you won't be able to ensure DB consistency.. etc etc.

I would think you should just use the LUN and then automate a process with snapdrive/snapmanager to quiesce db, take a snapshot and then replicate that snapshot.

Hope this helps!

[FelixZhou · Accepted solution]

thanks, we figured out the multipath.

  --create a configuration file /etc/multipath.conf
     ...
     devices {
        device {
                vendor "NETAPP"
                product "LUN.*"
                path_grouping_policy "group_by_prio"
                path_checker "tur"
                features "3 queue_if_no_path pg_init_retries 50"
                hardware_handler "0"
                prio "ontap"
                failback immediate
                rr_weight "uniform"
                rr_min_io 128
                flush_on_last_del "yes"
                dev_loss_tmo "infinity"
                user_friendly_names yes
                retain_attached_hw_handler yes
                detect_prio yes
        }
      }
     ...
    --start services
     #systemctl reload multipathd.service